Dual relief valve of bsm for vehicle engine

ABSTRACT

A dual relief valve apparatus of a Balance Shaft and Oil Pump Module (BSM) of a vehicle engine may include the pump housing, and a primary relief valve and a secondary relief valve mounted inside the pump housing, wherein the primary relief valve and the secondary relief valve may be sequentially opened or closed, wherein the primary relief valve may be first opened to release a first oil by a first oil discharge pressure applied thereto and sequentially the secondary relief valve may be opened to release a second oil by a second oil discharge pressure applied thereto, the first oil discharge pressure being relatively smaller than the second oil discharge pressure.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No.10-2012-0154213 filed Dec. 27, 2012, the entire contents of which isincorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dual relief valve of a BALANCE SHAFT& OIL PUMP MODULE (BSM) for a vehicle engine. More particularly, thepresent invention relates to a dual relief valve of a BSM for a vehicleengine, which can maintain the pressure of oil discharged from the BSMfor the vehicle engine to be an appropriate pressure.

2. Description of Related Art

In general, the lubrication of a vehicle engine is very important toreduce frictional resistance inside the engine and to cool the inside ofthe engine.

The lubrication of the vehicle engine is usually performed on all partsfrom a valve apparatus to a cylinder as well as a major moving part. Forexample, the lubrication places a great deal of weight on not onlyreduction in frictional resistance of a crank shaft, a connecting rodand a piston in the major moving part but also cooling of the piston andcylinder. The sealing performance of the piston and the cylinder ismaintained by engine oil.

Engine oil for lubrication is injected into the engine. The engine oilis pressure-fed to each lubricating part by a BSM.

Here, the BSM represents an oil pump or a balance shaft & oil pumpmodule having the oil pump as a module.

For example, the BSM is an apparatus that absorbs oil stored in an oilfan and supplies the absorbed oil to each lubricating part requiringlubrication. The oil pumped by the BSM is increased to a high pressureinside the BSM. The oil discharged in a high-pressure state from the BSMmay apply impact and damage to an oil filter or lubrication circuit.

Therefore, a relief valve for maintaining the pressure of the pumpingoil to be an appropriated pressure is provided to an oil discharge portof the BSM.

In a case where the pressure of oil discharged toward a main gallery ofthe engine from the BSM is increased to an appropriate pressure or more,the relief valve form a bypass flow path along which a portion of theoil discharged from the BSM is returned to the BSM or the oil fan, sothat it is possible to maintain the pressure of the oil discharged fromthe BSM to be an appropriate pressure, and particularly to prevent thedamage of the main gallery due to a high pressure of the oil dischargedfrom the BSM.

FIGS. 1 and 2 are perspective and sectional views showing a conventionalrelief valve of a BSM.

As shown in FIGS. 1 and 2, the relief valve is a valve that is mountedat one side of a pump housing 100 to be opened/closed by the pressure ofoil discharged from the BSM. The relief valve is configured to include aplunger 130 opening/closing a relief aperture (not shown) positioned ina valve groove 110 formed at the one side of the pump housing 100 tobypass a portion of the oil pumped from the pump housing 100, and aspring 140 elastically supporting the plunger 130 from the lowerposition thereof.

Here, undescribed reference numeral 120 represents a plug, andundescribed reference numeral 150 represent an oil discharge aperture.

Thus, the plunger of the relief valve directly receives the pressure ofthe oil pumped and discharged from the BSM. When the pressure of oildischarged from the BSM is remarkably increased, the plunger of therelief valve is pushed by the pressure of the oil discharged from theBSM, thereby opening the relief aperture.

If the plunger opens the relief aperture as described above, a portionof the pumping oil is bypassed through the relief aperture to bereturned toward the BSM or an oil fan.

However, in the BSM to which a conventional single-type relief valve isapplied, fuel efficiency and output loss occur due to excessive drivingtorque. Particularly, since the BSM uses a method in which the reliefvalve is simply opened or closed in response to the pressure of oildischarged therefrom, the amount of the oil discharged from the BSM isnot properly controlled, and therefore, the BSM cannot effectively dealwith various operation regions, thereby causing loss of the BSM.

The information disclosed in this Background of the Invention section isonly for enhancement of understanding of the general background of theinvention and should not be taken as an acknowledgement or any form ofsuggestion that this information forms the prior art already known to aperson skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing adual relief valve of a BSM for a vehicle engine, which is configuredwith the combination of a primary relief valve and a secondary reliefvalve so that the amount of oil discharged from the BSM can beefficiently controlled while each relief valve is operated in connectionwith a low-speed region, a middle-low speed region and a high-speedregion, thereby minimizing loss of the BSM.

In an aspect of the present invention, a dual relief valve apparatus ofa Balance Shaft and Oil Pump Module (BSM) of a vehicle engine, which isa valve mounted inside a pump housing to be opened/closed by pressure ofoil discharged from the BSM, may include the pump housing, and a primaryrelief valve and a secondary relief valve mounted inside the pumphousing, wherein the primary relief valve and the secondary relief valveare sequentially opened or closed, wherein the primary relief valve isfirst opened to release a first oil by a first oil discharge pressureapplied thereto and sequentially the secondary relief valve is opened torelease a second oil by a second oil discharge pressure applied thereto,the first oil discharge pressure being relatively smaller than thesecond oil discharge pressure.

The primary relief valve may include a primary plunger slidablypositioned inside a primary valve groove formed in the pump housing tooperate therein, and a primary elastic member disposed beneath theprimary plunger inside the primary valve groove to elastically supportthe primary plunger.

The dual relief valve apparatus may further include a first reliefaperture formed in the pump housing and connected to the primary valvegroove.

The dual relief valve apparatus may further include an oil flow paththrough which the first oil is configured to pass is formed inside theprimary plunger of the primary relief valve, wherein the second oilflowed from a high pressure region in the pump housing through an upperportion of the primary plunger to the oil flow path is released throughthe first relief aperture via the oil flow path according to a movementof the primary plunger.

The first oil is released through the first relief aperture in startingto move the primary relief valve in a middle-low speed region at thesame time when movement of the primary relief valve is started in alow-speed region, and the opening of the primary relief valve isfinished before opening of the secondary relief valve.

The secondary relief valve may include a secondary plunger positionedinside a secondary valve groove formed in the pump housing to operatetherein, and a secondary elastic member disposed beneath the secondaryplunger inside the secondary valve groove to elastically support thesecondary plunger.

The dual relief valve apparatus may further include a second reliefaperture formed in the pump housing and connected to the secondary valvegroove.

The first relief aperture is positioned higher than the second reliefaperture.

The second oil in the secondary valve groove is released through thesecond relief aperture by starting to move the secondary relief valve ina high-speed region formed in the pump housing.

Other aspects and exemplary embodiments of the invention are discussedinfra.

Advantages of the relief valve of the BSM for the vehicle engineaccording to the present invention are described as follows.

The dual relief valve of the BSM is configured with the combination of aprimary relief valve and a second relief valve, so that oil is releasedthrough a primary relief valve at a low pressure in a low-speed regionand a middle-low speed region, and the oil is released through asecondary relief valve at a high pressure in a high-speed region. Thus,the amount of oil discharged from the BSM can be pumped as much as theamount of oil required in an actual vehicle engine, and accordingly,loss of the BSM can be minimized. As a result, it is possible to reducedriving torque, to improve fuel efficiency and to minimize output loss.

The methods and apparatuses of the present invention have other featuresand advantages which will be apparent from or are set forth in moredetail in the accompanying drawings, which are incorporated herein, andthe following Detailed Description, which together serve to explaincertain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the mounting position of aconventional relief valve of a BSM.

FIG. 2 is a sectional view showing the conventional relief valve of theBSM.

FIG. 3 is a sectional view showing a dual relief valve of a BSMaccording to an exemplary embodiment of the present invention.

FIGS. 4A to 4C are sectional views showing an operating state of thedual relief valve of the BSM according to the exemplary embodiment ofthe present invention.

FIG. 5 is a graph comparing the performance of the dual relief valve ofthe BSM according to the exemplary embodiment of the present inventionwith the performance of the conventional relief valve.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variouspreferred features illustrative of the basic principles of theinvention. The specific design features of the present invention asdisclosed herein, including, for example, specific dimensions,orientations, locations, and shapes will be determined in part by theparticular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Hereinafter reference will now be made in detail to various embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings and described below. While the invention will bedescribed in conjunction with exemplary embodiments, it will beunderstood that present description is not intended to limit theinvention to those exemplary embodiments. On the contrary, the inventionis intended to cover not only the exemplary embodiments, but alsovarious alternatives, modifications, equivalents and other embodiments,which may be included within the spirit and scope of the invention asdefined by the appended claims.

FIG. 3 is a sectional view showing a dual relief valve of a BSMaccording to an exemplary embodiment of the present invention.

As shown in FIG. 3, the dual relief valve of the BSM is configured withthe combination of a primary relief valve releasing a primary oil at alow pressure and a secondary relief valve releasing a secondary oil at ahigh pressure, to efficiently pump the amount of oil discharged in alow-speed region, a middle-low speed region and a high-speed region,thereby minimizing loss of the BSM.

To this end, two parallel vertical valve grooves for mounting the reliefvalve, i.e., a primary valve groove 13 and a secondary valve groove 18are respectively formed at positions adjacent to one internal side of apump housing 10, e.g., a place in which an oil discharge aperture 21having pumping oil discharged therethrough is formed. Each of theprimary and secondary valve grooves 13 and 18 communicates with ahigh-pressure region 22 at an upper portion thereof and simultaneouslycommunicates with a low-pressure region 23 at a side portion thereof.

Accordingly, the oil from the upper portion communicating with thehigh-pressure region 22 can be released to the side portioncommunicating with the low-pressure region 23.

A primary relief valve 11 and a secondary relief valve 12 are mounted inthe primary valve groove 13 and the secondary valve groove 18,respectively. The primary and secondary relief valves 11 and 12 mounteddescribed above can release the oil while being sequentiallyopened/closed.

For example, the primary relief valve 11 is first opened under alow-pressure condition, i.e., an oil discharge pressure relativelysmaller than that of the secondary relief valve 12 to release the oil.Continuously, the secondary relief valve 12 is opened under ahigh-pressure condition, i.e., an oil discharge pressure relativelygreater than that of the primary relief valve 11 to release the oil.

That is, the downward movement of the primary relief valve 11 is startedin the low-speed region and releases the oil through a first reliefaperture 17 at the same time when the opening of the primary reliefvalve 11 is started in the middle-low speed region.

Then, the primary relief valve 11 is further descended by the oildischarge pressure continuously applied so that the opening of theprimary relief valve 11 can be finished before the secondary reliefvalve 12 is opened.

At the same time when the opening of the primary relief valve 11 isfinished, the opening of the secondary relief valve 12 is started in thehigh-speed region, thereby releasing the oil through the relief aperture17.

Here, the time at which the primary and secondary relief valves aresequentially opened/closed may be changed by differently adjusting theelastic coefficients of primary and secondary springs described later.In this case, the oil discharge pressure for opening each of the primaryand secondary relief valves may be set through various calibrationslinked with each of the high-speed region, the middle-low speed regionand the high-speed region.

Each of the primary and secondary relief valves 11 and 12 is configuredwith the combination of a plunger and a spring, and can release the oilusing the plunger that performs a vertical operation by beingelastically supported by the spring in each valve groove.

To this end, the primary relief valve 11 includes a primary plunger 14vertically operated while being positioned inside the primary valvegroove 13 of the pump housing 10, and a primary spring 15 supporting thebottom surface of the primary plunger 14 at the inner bottom of theprimary valve groove 13.

Accordingly, if the oil discharge pressure greater than a predeterminedvalue is applied to an upper portion of the primary plunger 14, theprimary plunger 14 is descended downward while pressing the primaryspring 15. As a result, the oil can be released to the low-pressureregion 23 through the first relief aperture 17 formed at a side surfaceof the primary valve groove 13.

Particularly, an oil flow path 16 communicating from the top end to theside end of the primary plunger 14 is formed inside the primary plunger14, so that oil flowed from the upper portion of the primary plunger 14through the oil flow path 16 can be discharged to the first reliefaperture 17 through the side portion of the primary plunger 14.

In this case, the primary plunger 14 may be divided into an upperplunger head body and a lower plunger support body. The plunger headbody and the plunger support body may be integrally connected by ahorizontal rib, except the portion at which the vertical oil flow path16 is formed.

The secondary relief valve 12 includes a secondary plunger 19 verticallyoperated while being positioned inside the secondary valve groove 18 ofthe pump housing 10, and a secondary spring 20 supporting the bottomsurface of the secondary plunger 19 at the inner bottom of the secondvalve groove 18.

Accordingly, when the oil discharge pressure greater than apredetermined value is applied to an upper portion of the secondaryplunger 19, the secondary plunger 19 is descended downward whilepressing the secondary spring 20. As a result, the oil can be releasedto the low-pressure region 23 through the second relief aperture 27formed at a side surface of the secondary valve groove 18.

In an exemplary embodiment of the present invention, the first reliefaperture 17 is positioned higher than the second relief aperture 27.

The operating state of the relief valve of the BSM, configured asdescribed above, will be described as follows.

FIGS. 4A to 4C are sectional views showing are sectional views showingan operating state of the dual relief valve of the BSM according to theexemplary embodiment of the present invention.

As shown in FIG. 4A, in the operation of a vehicle engine, the movementof the primary plunger 14 of the primary relief valve 11 is started inthe low-speed region. Continuously, the primary plunger 14 is furthermoved downward in the middle-low speed region. As the oil flow path 16of the primary plunger 14 communicates with the first relief aperture 17formed in the primary valve groove 13, the oil can be primarily releasedwhile flowing from the high-pressure region 22 to the low-pressureregion 23 via the oil flow path 16 and the relief aperture 17.

As shown in FIG. 4B, when the operation region of the vehicle enginereaches the high-speed region, the primary plunger 14 of the primaryrelief valve 11 is further moved downward as the oil pressure increases.Accordingly, the first relief aperture 17 formed in the primary valvegroove 13 is blocked, so that the oil cannot be released through therelief aperture 17.

As shown in FIG. 4C, at the same time when the operation region of thevehicle engine reaches the high-speed region, the secondary relief valve12 operates to release the oil.

That is, the secondary plunger 14 of the secondary relief valve 12 ismoved downward by the oil discharge pressure. As the second reliefaperture 27 formed in the secondary valve groove 18 is opened by thesecondary plunger 19, the oil can be secondarily released while flowingfrom the high-pressure region 22 to the low-pressure region 23 via thesecond relief aperture 27.

FIG. 5 is a graph comparing the performance of the dual relief valve ofthe BSM according to the exemplary embodiment of the present inventionwith the performance of the conventional relief valve.

As shown in FIG. 5, the pressure of oil is changed depending on anincrease in speed (rpm).

In the dual relief valve of the present invention, the amount of oildischarged from the BSM can be variably controlled by the slashedportion in the variable graph as compared with the existing singlerelief valve. Thus, an unnecessary loss of the BSM can be minimized bypumping the amount of oil discharged from the BSM as much as the amountof oil required in an actual vehicle engine.

Accordingly, in an exemplary embodiment of the present invention, thedual relief valve releasing oil while being sequentially opened/closedaccording to the low-speed region, the middle-low speed region and thehigh-speed region is implemented, so that it is possible to efficientlycontrol the amount of oil discharged from the BSM, thereby minimizingloss of the BSM.

For convenience in explanation and accurate definition in the appendedclaims, the terms “upper”, “lower”, “inner” and “outer” are used todescribe features of the exemplary embodiments with reference to thepositions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of thepresent invention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteachings. The exemplary embodiments were chosen and described in orderto explain certain principles of the invention and their practicalapplication, to thereby enable others skilled in the art to make andutilize various exemplary embodiments of the present invention, as wellas various alternatives and modifications thereof. It is intended thatthe scope of the invention be defined by the Claims appended hereto andtheir equivalents.

What is claimed is:
 1. A dual relief valve apparatus of a Balance Shaftand Oil Pump Module (BSM) of a vehicle engine, which is a valve mountedinside a pump housing to be opened/closed by pressure of oil dischargedfrom the BSM, the dual relief valve apparatus comprising: the pumphousing; and a primary relief valve and a secondary relief valve mountedinside the pump housing, wherein the primary relief valve and thesecondary relief valve are sequentially opened or closed, wherein theprimary relief valve is first opened to release a first oil by a firstoil discharge pressure applied thereto and sequentially the secondaryrelief valve is opened to release a second oil by a second oil dischargepressure applied thereto, the first oil discharge pressure beingrelatively smaller than the second oil discharge pressure.
 2. The dualrelief valve apparatus of claim 1, wherein the primary relief valveincludes: a primary plunger slidably positioned inside a primary valvegroove formed in the pump housing to operate therein; and a primaryelastic member disposed beneath the primary plunger inside the primaryvalve groove to elastically support the primary plunger.
 3. The dualrelief valve apparatus of claim 2, further including: a first reliefaperture formed in the pump housing and connected to the primary valvegroove.
 4. The dual relief valve apparatus of claim 3, furtherincluding: an oil flow path through which the first oil is configured topass is formed inside the primary plunger of the primary relief valve,wherein the second oil flowed from a high pressure region in the pumphousing through an upper portion of the primary plunger to the oil flowpath is released through the first relief aperture via the oil flow pathaccording to a movement of the primary plunger.
 5. The dual relief valveapparatus of claim 4, wherein the first oil is released through thefirst relief aperture in starting to move the primary relief valve in amiddle-low speed region at the same time when movement of the primaryrelief valve is started in a low-speed region, and the opening of theprimary relief valve is finished before opening of the secondary reliefvalve.
 6. The dual relief valve apparatus of claim 3, wherein thesecondary relief valve includes: a secondary plunger positioned inside asecondary valve groove formed in the pump housing to operate therein;and a secondary elastic member disposed beneath the secondary plungerinside the secondary valve groove to elastically support the secondaryplunger.
 7. The dual relief valve apparatus of claim 6, furtherincluding: a second relief aperture formed in the pump housing andconnected to the secondary valve groove.
 8. The dual relief valveapparatus of claim 7, wherein the first relief aperture is positionedhigher than the second relief aperture.
 9. The dual relief valveapparatus of claim 1, wherein the secondary relief valve includes: asecondary plunger positioned inside a secondary valve groove formed inthe pump housing to operate therein; and a secondary elastic memberdisposed beneath the secondary plunger inside the secondary valve grooveto elastically support the secondary plunger.
 10. The dual relief valveapparatus of claim 9, further including: a second relief aperture formedin the pump housing and connected to the secondary valve groove.
 11. Thedual relief valve apparatus of claim 10, wherein the second oil in thesecondary valve groove is released through the second relief aperture bystarting to move the secondary relief valve in a high-speed regionformed in the pump housing.